<span>The economic system that was most prevalent in Europe of the Early Middle Ages was the manorial system, which some people equate with feudalism and some don't. During the Middle Ages, a mercantile system also developed slowly, until it became very important in the Late Middle Ages and, ultimately, dominant in the Renaissance.</span>
In its current form, the collection of the Old Testament books<span> was completed by the first century b.c. The individual </span>books<span> themselves, however, are much more ancient—some dating to the tenth and eleventh centuries b.c. or earlier. Because these works purport to tell the </span>history<span> of human origins, many of the </span>events occur<span> ...</span>
World War I completely changed the way wars were fought.
Trench warfare, which was the norm just a century ago was seen as an nonviable strategy.
Modern machines such as tanks and airplanes made trench warfare mostly about keeping ground and resulted in stalemates.
Also, it was the first time that modern tanks, planes and machine guns were being used for first time at such a large scale, resulting in an unprecedented level of death and carnage.
Military generals soon realized that time-honored military code of conducts were now obsolete and a completely new form of strategy was now required.
Because they got killed in the ship and so they wanted war but couldn’t get it
I think the 2nd answer is correct
